Liver is the organ that plays a major role in metabolism of human body and contains a series of enzymes as catalysts for drug oxidation, reduction and hydrolysis. At the same time, there are some other enzymes used for catalyzing the synthesis reaction of drugs with certain substances. The compound formed by drug molecules and substances combined will be excreted in urine or feces. According to the above metabolic pathway, drug metabolism can be defined as structural changes of a drug catalyzed by enzymes. After being taken into the body, almost every drug is going to be metabolized at certain degrees. The metabolites of the drug may have no activity or have similar activity as the original drug. Thus the metabolites continue to work to have therapeutic effect or toxicity.
Recently, there is a potential drug for treatment of liver cancer-188ReO-MN-16ET. A ligand H3-MN-16ET is reacted and labeled with radioactive 188Re to create 188ReO-MN-16ET. Then 188ReO-MN-16ET is dissolved in Lipiodol to form 188ReO-MN-16ET/Lipiodol, a diagnostic and therapeutic radiopharmaceutical for liver cancers. In order to learn hydrolysis metabolites of 188ReO-MN-16ET in rats, researchers have tried to synthesize the hydrolysis metabolite [N-(2-Thioethyl)-3-aza-19-carboxylic acid-3-(2-thioethyl)octadecanamdo]oxorhenium(V) (ReO-MN-16COOH). During the synthesis process, ReO-MN-16ET can be used as starting material and hydrolysis occurs when an acid or a base is used as a catalyst so as to get ReO-MN-16COOH theoretically. However, no reaction occurs under acid catalysis in practice and the product obtained under base catalysis contains no ReO-MN-16COOH. The results are not as expected. Thus there is a need to find out other compound able to create ReO-MN-16COOH after hydrolysis. The compound can be used as a standard of hydrolysis metabolites of non-radioactive 185Re-complex compound.